Solar cell

Abstract

A solar cell includes a silicon substrate and an electrode formed on the silicon substrate. The silicon substrate has at least 5 raised portions having a cross-sectional height (h) of 50 nm or more per 5 μm length. The electrode is formed from a composition for solar cell electrodes including a conductive powder, an organic vehicle, and a glass frit having a glass transition temperature (Tg) of about 150° C. to about 450° C.

What is claimed is: 
     
         1 . A solar cell, comprising:
 a silicon substrate; and   an electrode formed on the silicon substrate,   wherein the silicon substrate has at least 5 raised portions having a cross-sectional height (h) of 50 nm or more per 5 μm length, and   the electrode is formed from a composition for solar cell electrodes comprising a conductive powder, an organic vehicle, and a glass frit having a glass transition temperature (Tg) of about 150° C. to about 450° C.   
     
     
         2 . The solar cell according as claimed in  claim 1 , wherein the glass frit has a crystallization temperature (Tc) of about 300° C. to about 650° C. 
     
     
         3 . The solar cell according as claimed in  claim 1 , wherein the glass frit has a melting point (Tm) of about 350° C. to about 700° C. 
     
     
         4 . The solar cell according as claimed in  claim 1 , wherein the glass frit is formed of a metal oxide, the metal oxide including at least one elemental metal selected from tellurium (Te), lithium (Li), zinc (Zn), bismuth (Bi), lead (Pb), sodium (Na), phosphorus (P), germanium (Ge), gallium (Ga), cerium (Ce), iron (Fe), silicon (Si), tungsten (W), magnesium (Mg), molybdenum (Mo), cesium (Cs), strontium (Sr), titanium (Ti), tin (Sn), indium (In), vanadium (V), barium (Ba), nickel (Ni), copper (Cu), potassium (K), arsenic (As), cobalt (Co), zirconium (Zr), manganese (Mn), aluminum (Al), and boron (B). 
     
     
         5 . The solar cell according as claimed in  claim 1 , wherein the glass frit includes at least one selected from a Bi—Te—O glass frit, a Pb—Bi—O glass frit, a Pb—Te—O glass frit, a Te—B—O glass frit, a Te—Ag—O glass frit, a Pb—Si—O glass frit, a Bi—Si—O glass frit, a Te—Zn—O glass frit, a Bi—B—O glass frit, a Pb—B—O glass frit, a Bi—Mo—O glass frit, a Mo—B—O glass frit, and a Te—Si—O glass frit. 
     
     
         6 . The solar cell according as claimed in  claim 1 , wherein the glass frit has a particle diameter of 0.1 μm to 10 μm. 
     
     
         7 . The solar cell according as claimed in  claim 1 , wherein the composition for solar cell electrodes includes:
 about 60 wt % to about 95 wt % of the conductive powder;   about 0.1 wt % to about 20 wt % of the glass frit; and   about 1 wt % to about 30 wt % of the organic vehicle.   
     
     
         8 . The solar cell according as claimed in  claim 1 , wherein the composition for solar cell electrodes further includes one or more of a dispersant, a thixotropic agent, a plasticizer, a viscosity stabilizer, an anti-foaming agent, a pigment, a UV stabilizer, an antioxidant, and a coupling agent.